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    <div class="refentry" id="glGetUniform">
      <div class="titlepage"/>
      <div class="refnamediv">
        <h2>Name</h2>
        <p>glGetUniform — Returns the value of a uniform variable</p>
      </div>
      <div class="refsynopsisdiv">
        <h2>C Specification</h2>
        <div class="funcsynopsis">
          <table style="border: 0; cellspacing: 0; cellpadding: 0;" class="funcprototype-table">
            <tr>
              <td>
                <code class="funcdef">void <strong class="fsfunc">glGetUniformfv</strong>(</code>
              </td>
              <td>GLuint <var class="pdparam">program</var>, </td>
            </tr>
            <tr>
              <td> </td>
              <td>GLint <var class="pdparam">location</var>, </td>
            </tr>
            <tr>
              <td> </td>
              <td>GLfloat *<var class="pdparam">params</var><code>)</code>;</td>
            </tr>
          </table>
          <div class="funcprototype-spacer"> </div>
          <table style="border: 0; cellspacing: 0; cellpadding: 0;" class="funcprototype-table">
            <tr>
              <td>
                <code class="funcdef">void <strong class="fsfunc">glGetUniformiv</strong>(</code>
              </td>
              <td>GLuint <var class="pdparam">program</var>, </td>
            </tr>
            <tr>
              <td> </td>
              <td>GLint <var class="pdparam">location</var>, </td>
            </tr>
            <tr>
              <td> </td>
              <td>GLint *<var class="pdparam">params</var><code>)</code>;</td>
            </tr>
          </table>
          <div class="funcprototype-spacer"> </div>
          <table style="border: 0; cellspacing: 0; cellpadding: 0;" class="funcprototype-table">
            <tr>
              <td>
                <code class="funcdef">void <strong class="fsfunc">glGetUniformuiv</strong>(</code>
              </td>
              <td>GLuint <var class="pdparam">program</var>, </td>
            </tr>
            <tr>
              <td> </td>
              <td>GLint <var class="pdparam">location</var>, </td>
            </tr>
            <tr>
              <td> </td>
              <td>GLuint *<var class="pdparam">params</var><code>)</code>;</td>
            </tr>
          </table>
          <div class="funcprototype-spacer"> </div>
        </div>
      </div>
      <div class="refsect1" id="parameters">
        <h2>Parameters</h2>
        <div class="variablelist">
          <dl class="variablelist">
            <dt>
              <span class="term">
                <em class="parameter">
                  <code>program</code>
                </em>
              </span>
            </dt>
            <dd>
              <p>Specifies the program object to be
            queried.</p>
            </dd>
            <dt>
              <span class="term">
                <em class="parameter">
                  <code>location</code>
                </em>
              </span>
            </dt>
            <dd>
              <p>Specifies the location of the uniform variable
            to be queried.</p>
            </dd>
            <dt>
              <span class="term">
                <em class="parameter">
                  <code>params</code>
                </em>
              </span>
            </dt>
            <dd>
              <p>Returns the value of the specified uniform
            variable.</p>
            </dd>
          </dl>
        </div>
      </div>
      <div class="refsect1" id="description">
        <h2>Description</h2>
        <p><code class="function">glGetUniform</code> returns in
    <em class="parameter"><code>params</code></em> the value(s) of the specified
    uniform variable. The type of the uniform variable specified by
    <em class="parameter"><code>location</code></em> determines the number of values
    returned. If the uniform variable is defined in the shader as a
    boolean, int, unsigned int, or float, a single value will be returned. If it
    is defined as a vec2, ivec2, uvec2, or bvec2, two values will be
    returned. If it is defined as a vec3, ivec3, uvec3, or bvec3, three
    values will be returned, and so on. To query values stored in
    uniform variables declared as arrays, call
    <code class="function">glGetUniform</code> for each element of the array.
    To query values stored in uniform variables declared as
    structures, call <code class="function">glGetUniform</code> for each
    field in the structure. The values for uniform variables
    declared as a matrix will be returned in column major
    order.</p>
        <p>The locations assigned to uniform variables are not known
    until the program object is linked. After linking has occurred,
    the command
    <a class="citerefentry" href="glGetUniformLocation.xhtml"><span class="citerefentry"><span class="refentrytitle">glGetUniformLocation</span></span></a>
    can be used to obtain the location of a uniform variable. This
    location value can then be passed to
    <code class="function">glGetUniform</code> in order to query the current
    value of the uniform variable. After a program object has been
    linked successfully, the index values for uniform variables
    remain fixed until the next link command occurs. The uniform
    variable values can only be queried after a link if the link was
    successful.</p>
      </div>
      <div class="refsect1" id="notes">
        <h2>Notes</h2>
        <p>If an error is generated, no change is made to the
    contents of <em class="parameter"><code>params</code></em>.</p>
      </div>
      <div class="refsect1" id="errors">
        <h2>Errors</h2>
        <p><code class="constant">GL_INVALID_VALUE</code> is generated if
    <em class="parameter"><code>program</code></em> is not a value generated by
    OpenGL.</p>
        <p><code class="constant">GL_INVALID_OPERATION</code> is generated if
    <em class="parameter"><code>program</code></em> is not a program object.</p>
        <p><code class="constant">GL_INVALID_OPERATION</code> is generated if
    <em class="parameter"><code>program</code></em> has not been successfully
    linked.</p>
        <p><code class="constant">GL_INVALID_OPERATION</code> is generated if
    <em class="parameter"><code>location</code></em> does not correspond to a valid
    uniform variable location for the specified program object.</p>
      </div>
      <div class="refsect1" id="associatedgets">
        <h2>Associated Gets</h2>
        <p><a class="citerefentry" href="glGetActiveUniform.xhtml"><span class="citerefentry"><span class="refentrytitle">glGetActiveUniform</span></span></a>
    with arguments <em class="parameter"><code>program</code></em> and the index of an active
    uniform variable</p>
        <p><a class="citerefentry" href="glGetProgramiv.xhtml"><span class="citerefentry"><span class="refentrytitle">glGetProgramiv</span></span></a>
    with arguments <em class="parameter"><code>program</code></em> and
    <code class="constant">GL_ACTIVE_UNIFORMS</code> or
    <code class="constant">GL_ACTIVE_UNIFORM_MAX_LENGTH</code></p>
        <p><a class="citerefentry" href="glGetUniformLocation.xhtml"><span class="citerefentry"><span class="refentrytitle">glGetUniformLocation</span></span></a>
    with arguments <em class="parameter"><code>program</code></em> and the name of a
    uniform variable</p>
        <p>
          <a class="citerefentry" href="glIsProgram.xhtml">
            <span class="citerefentry">
              <span class="refentrytitle">glIsProgram</span>
            </span>
          </a>
        </p>
      </div>
      <div class="refsect1" id="versions">
        <h2>API Version Support</h2>
        <div class="informaltable">
          <table style="border-collapse: collapse; border-top: 2px solid ; border-bottom: 2px solid ; border-left: 2px solid ; border-right: 2px solid ; ">
            <colgroup>
              <col style="text-align: left; "/>
              <col style="text-align: center; " class="firstvers"/>
              <col style="text-align: center; " class="lastvers"/>
            </colgroup>
            <thead>
              <tr>
                <th style="text-align: left; border-right: 2px solid ; ">
                 
            </th>
                <th style="text-align: center; border-bottom: 2px solid ; " colspan="2">
                <span class="bold"><strong>OpenGL ES API Version</strong></span>
            </th>
              </tr>
              <tr>
                <th style="text-align: left; border-right: 2px solid ; border-bottom: 2px solid ; ">
                <span class="bold"><strong>Function Name</strong></span>
            </th>
                <th style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">
                <span class="bold"><strong>2.0</strong></span>
            </th>
                <th style="text-align: center; border-bottom: 2px solid ; ">
                <span class="bold"><strong>3.0</strong></span>
            </th>
              </tr>
            </thead>
            <tbody>
              <tr>
                <td style="text-align: left; border-right: 2px solid ; border-bottom: 2px solid ; ">
                  <code class="function">glGetUniformfv</code>
                </td>
                <td style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">✔</td>
                <td style="text-align: center; border-bottom: 2px solid ; ">✔</td>
              </tr>
              <tr>
                <td style="text-align: left; border-right: 2px solid ; border-bottom: 2px solid ; ">
                  <code class="function">glGetUniformiv</code>
                </td>
                <td style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">✔</td>
                <td style="text-align: center; border-bottom: 2px solid ; ">✔</td>
              </tr>
              <tr>
                <td style="text-align: left; border-right: 2px solid ; ">
                  <code class="function">glGetUniformuiv</code>
                </td>
                <td style="text-align: center; border-right: 2px solid ; ">-</td>
                <td style="text-align: center; ">✔</td>
              </tr>
            </tbody>
          </table>
        </div>
      </div>
      <div class="refsect1" id="seealso">
        <h2>See Also</h2>
        <p><a class="citerefentry" href="glCreateProgram.xhtml"><span class="citerefentry"><span class="refentrytitle">glCreateProgram</span></span></a>,
        <a class="citerefentry" href="glLinkProgram.xhtml"><span class="citerefentry"><span class="refentrytitle">glLinkProgram</span></span></a>,
        <a class="citerefentry" href="glUniform.xhtml"><span class="citerefentry"><span class="refentrytitle">glUniform</span></span></a></p>
      </div>
      <div class="refsect1" id="Copyright">
        <h2>Copyright</h2>
        <p>
            Copyright <span class="trademark"/>© 2003-2005 3Dlabs Inc. Ltd.
            Copyright <span class="trademark"/>© 2010-2014 Khronos Group.
            This material may be distributed subject to the terms and conditions set forth in
            the Open Publication License, v 1.0, 8 June 1999.
            <a class="link" href="http://opencontent.org/openpub/" target="_top">http://opencontent.org/openpub/</a>.
        </p>
      </div>
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